Abstract:
In such a coherent system, the underlying assumption is that the channel does not change during one frame of data. Thus, it can also be interpreted as the frame length is chosen such that the path gain change during one frame is negligible. This is basically the quasi-static fading assumption that we have used so far. There is a bandwidth penalty due to the number of transmitted pilot symbols. Of course, choosing a longer frame reduces this bandwidth penalty; however, on the other hand, the quasi-static assumption is less valid for longer frames. So, there is a compromise between the frame length and the accuracy of the channel estimation. DSTBC requires that the transmission of symbols is known to the receiver at the beginning and hence is not truly differential. So, we can interpret as the joint channel and data estimation which can lead to error propagation.
